Published Ley lines

One of the frustrating things about ley publications is that the mark points
of leys are published as either descriptive text or lines on a map, rather than the national grid refs of
the sites. All of which makes it hellishly difficult to reproduce the work, as
the points have to be back-worked on modern maps before the quality can be
evaluated. Watkins at least had the excuse that it appears that the Ordnance
Survey National Grid system was not in operation when he wrote his book, and the
maps he used predate the 1" series.